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United States Patent |
5,733,374
|
Ekenberg
|
March 31, 1998
|
Painting booth and robotic painting installation therefor
Abstract
A robot installation for painting objects inside a painting booth (CA)
having walls (WA, WB) isolating the object (AU) to be painted from the
surroundings, is suitably integrated in the booth walls in order to save
interior booth space and achieve a robot operation better adapted to the
painting process. The installation includes at least one main robot shaft
(RS) associated with a painting tool and protruding through at least one
slot (LS) penetrating the booth walls for servo-controlled movements along
such slots and possibly also in the direction of and/or about the axis of
the shaft. Servo-drive means are disposed for controlling the robot shaft
movements in accordance with a preprogrammed motional pattern for the
painting tool, including tracking of a travelling object to be painted.
The slot is disposed on a rotatable element e.g., a disk or cylinder
(CD,SC) supported in or on the booth walls, and the servo-drive means
includes means for controlling the rotational movements of the rotatable
element in accordance with a preprogrammed motional pattern.
Inventors:
|
Ekenberg; Tor (P.O. Box 3014, N-4300 Sandnes, NO)
|
Appl. No.:
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578540 |
Filed:
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January 19, 1996 |
PCT Filed:
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July 19, 1993
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PCT NO:
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PCT/NO93/00117
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371 Date:
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January 19, 1996
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102(e) Date:
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January 19, 1996
|
PCT PUB.NO.:
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WO95/03133 |
PCT PUB. Date:
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February 2, 1995 |
Current U.S. Class: |
118/323; 118/326 |
Intern'l Class: |
B05B 003/00; B05B 001/28 |
Field of Search: |
118/323,326,305,324
318/568.11,568.12,568.13
|
References Cited
U.S. Patent Documents
4611695 | Sep., 1986 | Kato et al. | 118/323.
|
4920500 | Apr., 1990 | Hetland et al. | 118/323.
|
5213620 | May., 1993 | Meyer | 118/323.
|
Foreign Patent Documents |
0 536 459 A1 | Apr., 1993 | EP.
| |
9114509 | Oct., 1991 | WO.
| |
Primary Examiner: Czaja; Donald E.
Assistant Examiner: Padsell; Calvin
Attorney, Agent or Firm: Bacon & Thomas
Claims
I claim:
1. A painting booth and robotic installation for painting of objects inside
the booth, the booth having walls for isolating an object to be painted
from the surroundings, at least one of said walls including at least one
elongate slot penetrating the wall, said robotic installation comprising
at least one robot shaft connected to a painting tool and protruding
through said at least one slot for robotic controlled servo-controlled
movements at least along the length of said slot, and servo-drive means
positioned and arranged for controlling said robot shaft movements in
accordance with a preprogrammed movement pattern for said painting tool;
said slot being disposed on a rotatable element connected to the at least
one wall and having a slot length extending generally parallel to the at
least one wall, the servo-drive means comprising means positioned and
arranged for controlling the rotational movements of said rotatable
element in accordance with a preprogrammed movement pattern.
2. The painting booth and robotic installation as claimed in claim 1,
wherein said rotatable element comprises a circular disc disposed for
rotational movements in a plane extending parallel or in coincidence with
the plane of said booth wall, said slot length extending generally along a
diameter of said disc.
3. The painting booth and robotic installation as claimed in claim 1,
wherein said rotatable element comprises a hollow cylinder disposed for
rotational movement about an axis extending parallel with said wall, said
robot shaft protruding through said slot, said slot length extending
substantially parallel with said rotational axis.
4. The painting booth and robotic installation as claimed in claim 3,
wherein the robot shaft is disposed for translational movements along the
slot length under the control of the servo-drive means.
5. The painting booth and robotic installation as claimed in claim 3,
wherein the robot shaft is disposed for pivotal movements in the slot, and
is controlled by the servo-drive means at least about a pivot axis located
inside the hollow cylinder.
6. The painting booth and robotic installation as claimed in claim 5,
wherein the servo-drive means is located within said hollow cylinder and
is positioned and arranged arranged to actuate the movements of said robot
shaft in the slot by means of pivotal motions about at least two axes.
7. The painting booth and robotic installation as claimed in claim 6,
wherein the robot shaft is connected with the painting tool through a
manipulator link means having at least one axis of motion.
8. The painting booth and robotic installation as claimed in claim 5,
wherein the robot shaft is connected with the painting tool through a
manipulator link means having at least one axis of motion.
9. The painting booth and robotic installation as claimed in claim 1,
wherein the robot shaft is connected with the painting tool through a
manipulator link means having at least one axis of motion.
10. The painting booth and robotic installation as claimed in claim 1,
wherein the robotic installation is positioned and arranged arranged to
control movement of the robot shaft along and about the axis of the shaft.
11. The painting booth and robotic installation as claimed in claim 9,
wherein the connection of the robot shaft with the painting tool is
arranged to enable movement of the manipulator link means about at least
three axes of motion.
Description
This application is a National Stage Application filed under 35. U.S.C. 371
PCT/NO93/00117 filed Jul. 19, 1993.
FIELD OF THE INVENTION
The present invention is related to a painting booth and robot installation
for painting objects inside the painting booth, wherein the booth has
walls isolating the object to be painted from the surroundings.
RELATED ART
Programmable robots are generally known in the art and well described in
the literature. Special types of such robots are designed to be used for
painting of certain objects, e.g. motor cars, and a robot of this type may
be "taught" or preprogrammed by a skilled operator to perform the
appropriate movements of a painting tool in order to apply a prescribed
layer of paint to a selected part of the motor car body.
Painting of motor cars on an industrial scale usually takes place in
painting booths, through which the car bodies are moved on conveyors in
line succession. Such booths may secure sufficient isolation of the health
injurious painting areas from the environments.
For external painting of car bodies in such booths, simple and economical
reciprocators or the like are usually used. Apparatus of this type may
have a sufficient range of reciprocal motion in the vertical direction,
but have rather limited ranges of motion in the transverse direction of
the painting booth, and practically no option for tracking the object to
be painted in the direction of the conveyor motion through the booth.
Several such reciprocators having overlapping working ranges along the
length of direction of the -booth must then be used to maintain a
reasonable conveyor speed and paint coverage.
In order to achieve a uniform layer of paint and optimum painting quality,
the paint must be sprayed from the painting tool in a controlled manner
normal to the surface to be covered. The motion pattern of the tool must
then be correspondingly programmed in relation to the curved surfaces and
edges of the car body. This can only be accomplished by means of robot
manipulators with six or more axes of motion, which also would allow
efficient tracking of the object to be painted and higher conveyor speed
through the painting booth. Such robots must then be located in the
painting booth itself, which would require considerably wider booths than
with the reciprocator embodiment discussed above.
Wider booths would, however, require larger volume flow of venting air
through the booth, and the extended movements of the manipulator parts of
robots with many axes of motion, which are located within the booth, may
well set up turbulence or disturbance in the air flow.
It is, however, essential that the flow of air along the object to be
painted is uniform, in order not to disturb the dispersed atomized paint
particles directed from the painting tool towards the surfaces to be
uniformly painted.
As explained above, both the use of wall mounted reciprocator and location
of advanced robots within the painting booth have certain disadvantages.
It is therefore a main object of the present invention to provide a robot
installation that to a great extent would overcome all such disadvantages.
It should be noted, however, that the present invention is solely directed
to the mounting and installation for robots for the above and similar
purposes and is not concerned with the design or construction of the
painting robots per se, or with the programming of robots for efficient
and satisfactory painting operations consistent with the form and
movements of the objects to be painted.
Such design and programming are well described elsewhere, e.g. in GB Pat.
No. 1.431.413 and U.S. Pat. No. 4,920,500 owned in common with the present
application.
SUMMARY OF THE INVENTION
This invention concerns a painting booth and robot installation for
painting objects inside the painting booth, wherein the booth has walls
isolating the object to be painted from the surroundings, and wherein the
robot installation comprises at least one robot shaft associated with
i.e., connected to, a painting tool and protruding through at least one
slot penetrating a booth wall for servo-controlled movement along the
length of said slot and possibly also in the direction of and/or about the
axis of said shaft, and servo-drive means controlling said robot shaft
movements in accordance with a preprogrammed movement pattern for said
painting tool. The slot length extends substantially parallel to the booth
wall penetrated by the slot.
More specifically, a novel feature of the invention is that the slot is
disposed on a rotatable element supported in or on a painting booth wall
or walls, the servo-drive means comprising means for controlling the
rotational movements of the rotatable element in accordance with the
preprogrammed movement pattern.
The rotatable element may be a circular disc disposed for rotational
movements in a plane identical or parallel with the plane of a booth wall,
the slot length extending preferably along a diameter of the disc, or
alternatively a preferably hollow cylinder disposed for rotational
movements about a preferably vertical axis in or parallel with one of the
booth walls, with the robot shaft protruding through at least one slot
having a length extending substantially parallel with the rotational axis.
In both cases, efficient tracking in the travelling direction of the
object to be painted is achieved by rotation of the rotatable element,
possibly in combination with the movements of the robot shaft in the slot.
Advantageously, servo-drive means may be located within the hollow cylinder
for actuating the movements of the robot shaft in the slot by means of
pivotal motions about at least two axes. Also, in practice the robot shaft
may be connected with the painting tool through manipulator link means
having at least one and preferably three or more axes of motion.
BRIEF DESCRIPTION OF THE DRAWINGS
The robot installation according to the invention will now be further
explained by means of exemplified embodiments with reference to the
accompanying drawings, whereon:
FIG. 1 shows schematically a prior art painting booth having four painting
robots mounted inside the booth;
FIG. 2 shows schematically a painting booth having wall integrated robots
according to the invention;
FIG. 3 shows in principle the wall integration of a rotatable, slotted
element with protruding robot shaft according to the invention in a first
embodiment, in which said element is a slotted disc; and
FIGS. 4-6 show in principle the wall integration of rotatable slotted
elements with protruding robot shafts according to the invention according
to further embodiments, in which said elements are slotted cylinders.
DETAILED DESCRIPTION
As the present invention is not concerned with the design and construction
of robot manipulators or their component parts per se, but merely with
suitable painting booth wall integration of certain movable robot
elements, only the elements involved in such integration are illustrated
at least schematically in the figures and described below.
In FIG. 1, a convention painting booth CA having side walls WA and end
walls WB is shown schematically in section in a plan view with a motor car
body AU situated centrally in the booth. Also, four painting robots PR are
suitably located in the booth along the side walls for efficient painting
of the motor car body. These robots are advanced robot manipulators having
a large number of axes of motion and are consequently able to efficiently
perform detailed painting operations in accordance with a "pre-taught"
painting program adapted to the particular type of motor car body in
question.
Motor car bodies of this type are then moved in succession on a conveyor
(indicated by a thick arrow in FIG. 1) into and through the painting booth
CA, having inlet and outlet opening CI, CO for this purpose, the
intermittent conveyor speed being adapted to the painting program of the
robot manipulators PR that includes servo-drive device or devices for
allowing uniform paint coverage and optimum tracking of the moving car
bodies AU by the painting robots.
As evident from FIG. 1, the painting robots PR are in this conventional
embodiment occupying an unduly large portion of the booth volume. Also,
the large moving parts of the robot manipulators and their extensive
movements are likely to set up turbulence in the flow of venting air
through the booth, which may negatively affect the uniformity of the layer
of paint sprayed onto the car body surface in atomized form.
These disadvantages may be overcome to a large extent by means of a
narrower booth provided with simple reciprocators for the painting of the
motor cars by means of painting tools mounted on arms extending through
narrow slots in the booth walls and disposed for vertical reciprocating
movements along the slots, as discussed above.
However, with such a solution the quality of the painting would be largely
degraded, which is not feasible in many cases, where uniform paint
coverage and an always reliable painting process are primary requirements.
Hence, in order to combine a narrow booth with robot manipulators able to
produce high quality painting with reduced venting air agitation, it is
suggested according to the invention to integrate the robots with the
painting booth walls.
Such a painting booth CA with wall integrated robot installations IR is
illustrated in FIG. 2, in which a booth of the same general design as the
one in FIG. 1 is shown in the same format and with the same reference
characters indicating corresponding components. Here a booth embodiment
with two wall integrated robots and a shorter booth is shown in the upper
portion of the figure, whereas an embodiment with three wall integrated
robots and extended booth length is shown in the lower portion. In both
cases, the operating fields of the various robots are indicated with the
designation N. In this manner, robot installations with wide operations
fields and ample tracking abilities are realized in combination with
reduced painting booth dimensions.
One way of integrating a robot manipulator in a booth wall is illustrated
in FIG. 3. Here, a circular disc CD having a diametrical elongate slot LS
is rotatably supported in and substantially parallel with a plane
including the booth wall WA. Such rotatable support may be realized by any
suitable means known in the art. The range of rotation may be a full
revolution or a suitable fraction of the same, e.g. a half or a quarter of
a revolution. The main manipulator shaft RS protrudes through the
diametrical slot and is disposed for translational motions along the slot
length and in the axial direction of the shaft.
Thus, by means of the slotted disc CD and the protruding shaft RS, three
axes of motion may be realized for the robot manipulator, i.e. the
rotational axis of the disc, indicated by S1, the translational movement
of the shaft along the slot length, indicated by S2, and the translational
movement of said shaft in the direction of the shaft axis, indicated by S3
in the figure. By these means, coarse positioning of the painting tool in
accordance with a set painting program may be performed by a
servo-controlled drive means SD for the rotatable disc and the usual
servo-drive means for the robot shaft, in all three Cartesian coordinates
x, y and z indicated in FIG. 3, i.e., the length, width and height
dimension respectively, of the painting booth. An efficient tracking
function in the x direction may then be provided by the wall-based axis
S1, possibly in combination with the other wall-based axes of motion S2
and S3.
The finer and exact positioning of the tool is then achieved through the
axes of motion S4, S5, S6 provided by the wrist manipulator link ML, which
connects the robot shaft RS with the painting tool and is controlled by
the usual servo-drive means.
Another embodiment of the wall integration of said rotatable element of the
painting robot is illustrated in principle in FIG. 4. Here the rotatable
element is a hollow slotted cylinder SC supported vertically in in
substantially parallel with the booth wall for rotational movements about
the central axis of the cylinder. The main robot shaft protrudes through a
pair of mutually aligned slots LS extending through the cylinder walls and
having lengths that extend parallel with the cylinder axis.
The coarse robot movements in the directions of the said coordinates x, y
and z corresponding to the booth dimensions mentioned above, may in this
case be realized through the rotation of the cylinder SC about its central
axis, indicated by the axis of motion S1, together with translational
movements of the main robot shaft RS along and perpendicular to the slot
length, corresponding to the indicated axes of motion S2 and S3
respectively. Also, in this case an efficient tracking function in the x
direction may be achieved by means of the wall-based axes of motion S1, S2
and S3.
In FIG. 5, an embodiment of the same type as illustrated in FIG. 4, is
shown comprising a rotatable cylinder integrated in the booth wall, with
the only difference being that the main robot shaft RS is pivotally
supported in the cylinder itself, rather than disposed for translational
movements along the slot length. Thus, the latter translation movement is
here substituted by a pivotal movement in a considerably shorter pair of
cylinder slots LS, as indicated by the shown rotational axis of motion S2,
the other axes of motion S1 and S3 being the same as in FIG. 4.
In this manner the same coarse servo-controlled robot movements along the
said Cartesian axes x, y and z, and associated object tracking as
explained earlier may be realized.
In FIG. 6 there is shown a wall integrated rotatable element in the form of
a hollow cylinder SC. In this case, the cylinder is appropriately
supported on a more solid base, as the servo-drive machinery SD is located
into the cylinder itself, the main robot shaft protruding through a single
slot in the cylinder wall. Here, the wall-based coarse robot movements in
the x, y and z directions are realized by means of three rotational axes
of motion, S1, S2 and S3, respectively, which also may enable the intended
object tracking discussed above.
As in the embodiment shown in FIG. 3, also with the latter embodiments
illustrated in the FIGS. 4, 5 and 6, the finer servo-controlled movements
of the painting tool are performed about the additional axes of motion S4,
S5 and S6 of the wrist manipulator link ML.
With the wall integrated robot installations according to the invention,
considerably reduced dimensions of painting booths are achieved, while
maintaining large operational fields for the integrated robot
manipulators. Efficient tracking functions are provided in the direction
of the conveyor motion (the x direction) even with very narrow booths. Due
to the wall integration of several axes of motion of the robot
manipulators, a reduced number and size of movable components would be
operating in the interspace between the booth walls and the object to be
painted, e.g., a motor car body, which means less turbulence (disturbance)
in the venting air through the booth and thereby a more uniform paint
coverage.
Practical wall integrated test installations have shown that savings on the
order of 10-25% may be achieved in the width dimension of the booth (the y
direction). Due to more efficient tracking, a booth length reduction of up
to 25% also may be achieved in the length direction (the x direction).
Reduction on the order of 10-40% in the booth volume to be vented are then
obtainable, which means less venting air, less air turbulence and less
disturbance of the painting process.
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